Lights that may be for activating light-activated materials are disclosed. There are various materials that are activated by light. For example, dental restorative materials, dental sealants and orthodontic adhesives may include monomers and a photoinitiator. The photoinitiator may be sensitive to light of a particular wavelength, and when exposed to light of that wavelength of sufficient power and duration, activates the monomers so that they polymerize into a cured and durable polymer. Further, dental whiteners may be activated or accelerated by exposure to a particular light. In the medical field, light activated materials may include splints, stents, hard tissue restorations, and drugs which are activated within the human body by exposure to a particular light. In the construction field, various adhesives, coatings, insulation, and sealants may be activated by particular light. A particular application of such technology would be the activation or curing of structural, repair or coating materials, including underwater application of such materials, or application of such materials in space.